1. Field of the Invention
The present invention relates to a video special effect generating apparatus for processing a video signal so as to generate various video special effects on a picture.
2. Description of the Prior Art
Hitherto, various video special effects have been developed and realized by video special effect generating apparatuses. For example, such video special effects as image expansion, image contraction, image rotation, image defocusing, color changing, and image lighting-up or illuminating (effect of making an image as if it were illuminated with light) have been often employed in television programs and commercial productions and contributing to creation of impressive pictures.
An example of a conventional apparatus for generating the image lighting-up, or illuminating, effect is disclosed in Japanese Laid-open Patent Application No. 1-292975. A feature of this apparatus lies in a reading address generator. In this reading address generator, the distance between the position of each pixel of an input image and a predetermined specific line on the image plane is determined by a distance calculator. The determined distance is sent as a distance signal to a function generator which is composed of a position function generator and a luminance function generator. The position function generator converts the distance signal so as to give a desired positional deformation, and the luminance function generator converts the distance signal so as to give a desired luminance change. In an image subjected to this processing, when, for example, a sheet of paper placed on a Hat plane in the image is rounded into a cylindrical shape, the cylinder looks as if it were illuminated with light. That is, the conventional video special effect generating apparatus can generate the image lighting-up effect.
However, the conventional video special effect generating apparatus cannot generate more sophisticated video special effects like the effect of giving a lit-up object in the image with a qualitative appearance.